全文获取类型
收费全文 | 10751篇 |
免费 | 1044篇 |
国内免费 | 1320篇 |
专业分类
化学 | 851篇 |
晶体学 | 18篇 |
力学 | 656篇 |
综合类 | 283篇 |
数学 | 9310篇 |
物理学 | 1997篇 |
出版年
2024年 | 12篇 |
2023年 | 124篇 |
2022年 | 111篇 |
2021年 | 168篇 |
2020年 | 220篇 |
2019年 | 266篇 |
2018年 | 250篇 |
2017年 | 289篇 |
2016年 | 312篇 |
2015年 | 249篇 |
2014年 | 485篇 |
2013年 | 722篇 |
2012年 | 432篇 |
2011年 | 636篇 |
2010年 | 589篇 |
2009年 | 772篇 |
2008年 | 837篇 |
2007年 | 898篇 |
2006年 | 723篇 |
2005年 | 677篇 |
2004年 | 499篇 |
2003年 | 567篇 |
2002年 | 476篇 |
2001年 | 374篇 |
2000年 | 420篇 |
1999年 | 381篇 |
1998年 | 356篇 |
1997年 | 286篇 |
1996年 | 207篇 |
1995年 | 114篇 |
1994年 | 123篇 |
1993年 | 75篇 |
1992年 | 58篇 |
1991年 | 54篇 |
1990年 | 41篇 |
1989年 | 26篇 |
1988年 | 33篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 36篇 |
1984年 | 33篇 |
1983年 | 13篇 |
1982年 | 28篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 20篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1936年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
利用Banach空间中的锥理论和不动点定理讨论了非线性算子方程变号解的存在性,给出了E_u_0空间下非线性算子方程变号解至少有一个变号解、一个正解和一个负解的条件,并讨论了仅通过一个上解条件得出非线性算子方程变号解的存在性定理. 相似文献
52.
53.
张春芝 《数学的实践与认识》2017,(6):221-225
在直觉I-fuzzy拓扑空间中定义了内部度,并研究了它的一些性质,接着给出了直觉I-fuzzy拓扑空间内部算子的概念,最后得到了从拓扑的直觉I-Fuzzy内部算子I出发,得到一个直觉I-fuzzy拓扑r,再利用r定义的内部算子恰好回到了I等结论. 相似文献
54.
In this paper, a new variational formulation for a reaction-diffusion problem in broken Sobolev space is proposed. And the new formulation in the broken Sobolev space will be proved that it is well-posed and equivalent to the standard Galerkin variational formulation. The method will be helpful to easily solve the original partial differential equation numerically. And the method is novel and interesting, which can be used to deal with some complicated problem, such as the low regularity problem, the differential-integral problem and so on. 相似文献
55.
56.
Confinement effects on the electronic structure of M‐shell atoms: A study with explicitly correlated wave functions 下载免费PDF全文
Francisco J. Gálvez Enrique Buendía Antonio Sarsa 《International journal of quantum chemistry》2017,117(19)
The ground and some excited states of Na and Mg atoms confined at the center of a spherical box with impenetrable walls are studied. Variational wave functions including dynamic correlations and configuration mixing have been obtained. Level crossings induced by confinement have been analyzed in terms of the energy of the occupied orbitals of the M shell and the weight of the different configurations. Confinement effects on the correlation energy have been studied. The parameterized optimized effective potential and the variational Monte Carlo methods have been employed. A cut off‐factor has been included to account for the hard wall confinement. 相似文献
57.
Morteza RAHMANI 《数学研究及应用》2017,37(4):466-476
In this paper we discuss about $c$-frames, namely continuous frames. Since, $c$-frames are generalizations of discrete frames, we generalize some results of discrete frames to continuous version. We explain some results about relations of projections in Hilbert spaces and $c$-frames to characterize these frames. Also, we will specify (precisely) the synthesis and frame operators of Bochner integrable $c$-frames. Finally, we classify Hilbert-Schmidt operators by $c$-frames and express some new identities for Parseval $c$-frames. 相似文献
58.
In this paper, we mainly discuss the class of charming spaces. First, we show that there exists a charming space such that the Tychonoff product is not a charming space. Then we discuss some properties of charming spaces and give some characterizations of some class of charming spaces. Finally, we show that the Suslin number of an arbitrary charming rectifiable space is countable. 相似文献
59.
In this paper, we obtain that multilinear Calderón-Zygmund operators and their commutators with BMO functions are bounded on products of Herz-Morrey spaces with variable smoothness and integrability. The vector-valued setting of multilinear Calderón-Zygmund operators is also considered. 相似文献
60.
Tuğba Akman 《Applicable analysis》2017,96(3):461-482
In this study, proper orthogonal decomposition (POD) method is applied to diffusion–convection–reaction equation, which is discretized using space–time discontinuous Galerkin (dG) method. We provide estimates for POD truncation error in dG-energy norm, dG-elliptic projection, and space–time projection. Using these new estimates, we analyze the error between the dG and the POD solution, and the error between the exact and the POD solution. Numerical results, which are consistent with theoretical convergence rates, are presented. 相似文献